1. Field of Invention
The invention relates to a lighting device. More particularly, the invention relates to a candle-like lighting device.
2. Description of Related Art
The conventional candle lamp is designed based on tungsten filament, located at the center of a lamp cap. In this kind of candle lamp, the light source is the tungsten filament, locating within the cap. People have been familiar to the kind of lamp for a long period. However, the mechanism based on tungsten filament consumes electric power.
Recently, the light emitting diode (LED) light source has been well developed to provide an alternative choice for the lighting device. A disclosure of Taiwan Patent No. 532699 has disclosed a lamp based on LEDs. FIG. 1 is a drawing of a cross-sectional view, schematically illustrating a conventional lamp based on LEDs. In FIG. 1, the lamp 50 includes an electric base 52, and the LEDs 54 are disposed on the electric base 52. The power circuit 58 converts the usual power into the operation voltage for the LEDs 54 to emit light. The lamp cap 56, such as a glass cap, covers over the LEDs 54. The LED may replace the tungsten filament, resulting in saving power and other.
Noticeably, the LEDs 54 are disposed on the electric base 52 but not floating in the space. However, this design of the lamp in FIG. 1 is not in the same visual effect to the user, who has been got used to the candle lamp for long time.
Further, a disclosure of utility model patent of Taiwan Patent No. M345924 has disclosed another candle-like lamp using the LED as the light source. In addition, a cylindrical light guide body is used to guide the light to the other end. An external scattering structure is disposed on the cylindrical light guide body to scatter the light. However, the scattering structure is an external protruding part in the shape of candle flame.
Further, a disclosure of utility model patent of Taiwan Patent No. M371976 has disclosed the light guide body having an outer surface, composed of several regions with different slant angles, so as to scatter the light into a region within a larger solid angle.
Further, a disclosure of U.S. Pat. No. 6,218,785 has disclosed another lamp design also based on the LED. The cap has a chamber to receive the light from the LED. The counter surface with respect to the LED has a curving reflection surface and a central transparent region. The curving reflection surface reflects the light backward, and the central transparent region allows the light to pass and scatter to other direction.
However, more designs for the lamp based on the LED are still under developing.